Tin soaps and preparation thereof



Patented A1... 10, 1945 5 U ITED ST TES P TE T I orrlca arshaw Chemical corporation of Ohio Company. Elyria, Ohio, a

No Drawing. Application March 5, 1941,

Serial No. 881,858

scam (or. 260-414) This invention relates to tin soaps and particularly to tin soaps of aliphatic and cyclo-aliphatic mono-carboxylic acids having boiling points above 175 C. and melting points not above One object of the invention is to provide an improved process of reacting such acids with stannous hydroxide'to form such soaps, and a furthe ob ee is rodu basi in sea s of r j t c t p '10 a: varying from 0-05 to 1.2. This mode of reprebined tin than required by the formula such acids, that is, soaps containing more com- (RCOOhSn and of any degree of basicity up to and even beyond such as represented by the formula RCOOSnOH.

Attempts to produce satisfactory tin soap com-. positions have been unsuccessful to a greater or less degree. If precipitation methods were employed, hydrolysis proved troublesome resulting in the presence of both tin hydroxide and free acid in the product. Presumably neutral tin soaps existed in equilibrium with these hydrolysis products but so far as I am aware the point was never proved inasmuch as separation would be difilcult. If fusion methods were tried, the reaction failed to proceed or did not proceed to completion and so far as I know no successful fusion method has been developed heretofore.

So far as I am aware, no one has heretofore produced basic stannous soaps. These basic stannous soaps are useful as addition agents for lubricants and are superior to the neutral and acid soaps in that more metal can be introduced with less extraneous organic but with enough organic to insure proper dispersion in the lubriof (RCOOhSn and RCOQSnOH.- Indeed, I am able to produce tin soap compositions containing more tin than represented by the formula RCOOSnOH and being oil soluble and free from uncombined tin hydroxide.

The products which Iprefer to make might be empirically expressed by the formula sentation is adopted merely for convenience in defining the proportions or degree of-baslcity and is not proposed as 'a true formula. The usual representations for the neutral and fully basic salts are as shown above, namely, (RCOOJ ash and RCOOSnOH." I believe that in the prod ucts which I produce the basicity is mainly accounted for byfisupposing that these products are mixtures of the neutral and fully basiccompounds, the tin atom being bonded by one valency temperature above the decomposition temperature of Sn(OH)a, which is about 160 0., and then adding the stannous hydroxide in moist condition. While I do not fully understand the reason, I have found that this procedure results in a ready reaction under conditions where the oxide would not react well and suppresses the formation of oil insoluble materials whetherthe product be neutral or basic.

I am able to produce soa s of aliphatic and cents, and at the same time, the introduction of 35 fil l mene-eerbexylie acids having acids capable of causing corrosion'of engine parts is avoided. Considerable dimculty has been experienced also in avoiding'the production of materials which are insoluble in lubricating oils or mineral spirits. These dark and oil-insoluble 40 at a temperature above a d for best materials are believed to be stannic compounds or unreacted stannous oxide and some proposed methods of manufactureof the stannous soaps have included elaborate and expensive precautions to minimize the formation of these stannic compounds. It is important to. avoid the presence of tin oxides in the product since they are abrasive.

I have now discovered that I am able to produce stannous soaps ofthose aliphatic and cycloaliphatic mono-carboxylic acids which have meltsults recommend acids having boiling points not lowerthan2250. It is also desirable that the acids employed have melting points not higher than 160 .C. and preferably not above C.-

48 Aliphatic and cyclo-aliphatic mono-carboxylic acids of from 10 to 24 carbon atoms in the molecule are most. suitable and of these the compounds of from 15 to 18 carbon atoms are preferred.

j The following acids may be mentioned byway of example assuitable forreacti'onwith stannous hydroxide in accordance with my process, viz.', oleic, stearic, pelmitic, myristic, lauric, capric,

" and mixtures thereof, and acids and acid mixtures of the above indicated boilin'g and melting points obtained from petroleum (e. g., naph-,

thenics); linseed oil, corn .oil, soya bean oil, fish oil, tung oil, tall oil, and rosin. In the list of oils 'just recited, the acids obtained from petroleum drated stannous hydroxide added. while maintaining the temperature. The stannous hydroxide should be added slowly and stirring may be desirable toward the end of the reaction. The amount of tin hydroxide added may be such as to produce a neutral soap of the formula (RCOOhSn, but I prefer to use an amount to make basic scans of approximately the empirical formula :rSn(OH)z-Sn(OOCR)2 where :1: varies from 0.05 to 1.2. In the case of compositions where :r-is above 1.00, the reaction is difllcult on account of the viscous nature of the reaction mixture as the end point is approached. The value of a: should be at least 0.05 so as to make a substantial improvement over the neutral composition and to make sure that production errors will never carry the value as low as neutral, thereby range for the value of :c is therefore 0.05 to 1.0.

The water content (free water and water of hydration) of the tin hydroxide preferably is such that the elemental tin content of moist tinihytemperature in a thin film. There was very little reaction and considerable quantities of gray to black insoluble materials were formed. 7

Example IV produced according to Example III was added at insuring absence of free acid. A very desirable droxide material. of the formula Sn'(OH)-'a-xI-Ia0 is from to 60%, suitably from to The following specific examples will serve to illustrate the invention:

Example I P To 400 gramsof oleic acid of acid value 190 at a temperature of 210 C. was added, while heating was continued, 221 grams of moist stan-' nous hydrate (36.4% 3n, the remainder being OH and water, some of the water probably being chemically bound as water of hydration) at a rate .to prevent substantial lowering of the tem- Y perature. The materials reacted readily and almost completely under these conditions to form a tin soap.

- v Emmnle H To 200 grams of naphthenic acid of acid value 263 at a temperature of 210 C. was added, while heating was continued, 153 grams of moist stannous hydrate (36.4% Sn, the remainder being 0H and water, some of the water probably being chemically bound as water of hydration)-at a C. and held between that temperatureand 235 C- while 470 grams 0! moist stannous hydrate pulp was added slowly. The tin hydrate was freshly precipitated irom cold stannous chloride by cold I ammonia, filtered andwashed with water'and used with the moisture content resultins from such method of preparation (approximately 34% s The yield was of theoretical. The product was a clear, oily gel,"approximately a i-neutral tin'oleate (18% Sn).

, This example was du licated except that the 'tinhydrstewssiflrstdrledovermghtatrocm a temperature maintained within the range 235 C. to 250 C. 10 grams more of the tin hydrate paste employed in making the 16% soap of Example III. The result was a basic tin soap (approximately 26% Sn).

/ Example V To 900 grams of naphthenic acid or acid value 232 at a temperature of 210 C. to 225 C. was

added 650 grams of the tin hydrate paste described in Example 111. The product was a basic tin soap (24.2% Sn).

- Example VI Approximately 4 /2 pounds of oleic acid of acid value 195 were heated to 190 C. To this was added in small additions 2.4 pounds of moist warm (40 C. or higher) depositing about 25% of a pale, tan solid material (thought to .be an isomer) on cooling to normal room temperature (21C.).

Example VII The procedure of Example VI was followed except that no acid was added to compensate for loss by volatilization. The result was 5.30 pounds 0! a basic tin oleate containing 18.4% Sn. Thi material was a thin, tan colored liquid when warm (40 C. or higher) depositing about 40% of a pale tan solid material on cooling to normal room temperature (21 C.)

Example VIII Example IX Starting with 300 grams of the product'of Example 'VIII, additional tin hydroxide of the kind used in producing the composition of that example was cookedin at temperatures within the range 220 C. to'240" C. until the mass became as viscous as convenient to manipulate. The yield was 331 grams of a solid material of 38.9% tin content and soluble in lubricating oils, for

example, a naphthenic base, 500viscosity F.),red oil.

Having .thus described myyinvention, what I claimis: 1. A process for the production or basic tin soap compositions comprising reacting moist stannous hydroxide of the formula Sn(OH):-H:O, whose elemental tin content is;'irom25% to 60%. witha c scidhsvingaboillng point above 175 C. and a melting point between 75'-.C.

and

160 C., having trcm lo'to 24 carbon atoms to the molecule the batch being-maintained at a temperature not below 175 C. e

2. A process for the production of basic tin soap compositions comprising reacting moist stannous hydroxide of the formula Sn(OH)2-H2O, whose elementaltin-content is from to 60%, with a monocarboxylic acid, having a boiling point above 175 C. and a melting point between 160 and 175 C., having from 15 to 18 carbon atoms in the molecule, the temperature of the batchbein maintained between 190 C.- and 240 C.

4 t 3 4. A process for -the production ottin soaps, comprising reacting moist hydrated, stannous hydroxide with an organic carboxylic acid mixture having boiling points above 175 C. and

melting points between 100 C. and 175 C., havhydroxide of theformula Sn(OI-I):Hz'0 whose 3. A process for the production or tin soap compositions comprising reacting moist stannou hydroxide whose essential tincontent is'irom to with a carboxylic acid mixture having boiling points above 175 C. and melting points I between C. and C., the batch being maintained at a temperature not below C.

elemental tin content is .from 25% to 60% with an organic acid selected from the group consisting or naphthenicacids, tall oil acids and rosin.

.acids, the batch being maintained at a temperature not below 175 C. I

STANLEY B. Emo'rr. 

